Lock assemblage for adjustable leg rest



June 15, 1965' A. c. MOMMSEN ocx ASSEMBLAGE FOR ADJUSTABLE LEG- RESTINVENTOR. ADOLPH C. MOMMSEN 1%.

Fil ed Jap. 6, l964 ATTORNEYS United States Patent 3,189,385 LOCKASSEMBLAGE FOR ADlUSTAB-LE LEG REST Adolph C. Mornmsen, Minneapolis,Minn, assiguor to Metal-Matic, Inca, lvlinneapolis, Minn a corporationof Minnesota Filed Jan. 6, 19:34 Ser. No. 335,998 Claims. (Cl. 297-429)This invention relates generally to wheel chairs, and pertains moreparticularly to a lock assemblage or mechanism for maintaining anadjustable leg rest at a desired height with respect thereto.

One object of the invention is to provide a lock assemblage for legrests that will have extremely smooth operation. In this regard, it iswithin the contemplation of the invention to permit the leg rest to beeasily raised to an appropriate elevation for the user and to affordexcellent leverage that permits a ready and controlled lowering of theleg rest to a desired lower position. The invention also has as an aimthe locating of the lever or handle in a position that is readilyaccessible to the occupant of a wheel chair.

Another object of the invention is to provide a shield that isassociated with the lock assemblage, the shield mechanism preventinglint and dust from accumulating on the movable parts and therebycreating unsanitary conditions and interfering with the proper grippingaction that the assemblage is to provide.

A further object is to provide a lock assemblage of the foregoingcharacter that can be quickly assembled without the need for any specialtools or implements.

Still another object of the invention is to provide a lock assemblagefor adjustable leg rests that will not become damaged or marred, whichdamaging or marring would interfere with the proper operation of theassemblage. In this regard, it is an aim of the invention to employ akeeper which coaets with a rod that has a hard surface, the keeper beingformed of a material no harder than that of the rod. In this way, thekeeper, which is cocked or tilted to maintain the rod in a lockedcondition, does not score or mutilate the rod in any way and thecontinued smooth surface of the rod obviates any chance of theadjustment becoming jerky or irregular after a prolonged period of use.

These and other objects and advantages of my invention will more fullyappear from the following description, made in connection with theaccompanying drawing, wherein like reference characters refer to thesame or similar parts throughout the several views and in which:

FIGURE 1 is a perspective view showing a wheel chair equipped with alock assemblage constructed in accordance with the teachings of thepresent invention;

FIGURE 2 is a side elevational view of the leg rest as it appears inFIGURE 1, although a raised position of the leg rest has been shown inphantom outline;

FIGURE 3 is a fragmentary detail of the lock assemblage with portionsthereof broken away in order to illustrate to better advantage themanner in which the locking or gripping action is performed, and

FIGURE 4 is a sectional view taken in the direction of line 44 of FIGURE3.

Although the invention may be used with a variety of wheel chairconstructions, a typical wheel chair has been denoted in its entirety bythe reference numeral ill. The wheel chair that has been selected forillustrating the invention includes a folding frame 12 having an upperhorizontal tubular member 14 at each side, a lower horizontal tubularmember 16 at each side, and vertical legs 18 extending between thesetubular members 14, 16.

Before describing the adjustable leg rest with which my lock assemblageis used, it will be of advantage as far as background material isconcerned to describe briefly a non-adjustable leg rest which has beenindicated gen erally by the reference numeral 20. The leg rest 20comprises an inclined member 22 having a horizontal upper end 24 that isreceived in the tubular member 14 at the left of the wheel chair 1%.Intermediate the ends of the inclined member 22 is a branch tube 26 thatis received in the left lower tubular member 16. An L-shaped tubularmember 23 is attached to the lower end of the inclined member 22 throughthe agency of a U clamp 30. A bolt 32 produces the requisite clampingaction. In this way, a foot support 34 is retained at a fixed elevationwith respect to the wheel chair Ill and its frame 12.

An adjustable leg rest has been designated generally by the referencenumeral 36 and comprises an inverted L-shaped member 38 having an upperhorizontal projection 40. The adjustable leg rest 36 is intended to bedetachable and as can be discerned from FIGURE 2, there is a U-shapedspring 42 contained in the projection 40 that urges a detent 44downwardly with respect to a hole 46 formed in the right upperhorizontal tubular member 14. In addition to the upper horizontalprojection 4d of the L-shaped member 33, there is a vertical portionlabelled 48. At the lower end of the vertical portion 48 is a horizontalprojection 49' that is received in the lower horizontal tubular member16. The upper horizontal projection 41) on the L-shaped member 38 has abifurcated end 50 through which extends a pivot pin or bolt 52. I

The pin or bolt 52 serves as a pivot for an obtuse arm 54 having anelbow designated by the numeral 56 that is selectively positionable in amanner presently to be described. The leg rest generally denoted by thereference numeral 36 also includes a calf support 53. At the lower endof the obtuse arm 54 is an L-shaped tube as having a U clamp 62 and bolt64 for the purpose of attaching same to the arm 5- The lock assemblagefor maintaining the leg rest 36 at any desired elevation will now bedescribed. The assemblage includes an L-shaped rod 63 having arelatively hard surface. The reason for the hard surface will becomeclear as the description progresses. In this regard, though, it iscontemplated that the rod 68, as are other parts that have beendescribed and which will hereinafter be referred to, may be plated withchromium or otherwise hardened. Chrome plating naturally presents arelatively hard surface, but with respect to the rod 68 such surface mayalso conveniently have a zinc coating thereon which assists in producinga high degree of gripping action which will be explained hereinafter.The L-shaped construction of the rod 68 presents a relatively short leg70 and a relatively long leg 72. Aligned apertures 74 in the elbow 56 ofthe obtuse arm 54! permits the short leg '76 of the rod as to bepivotally attached to said arm 54. While the rod 6% is pivotallyconnected to the arm 54 at one end, the other end thereof has a stop inthe form of a split washer '76 that resides in a circumferential grooveformed at the end of the relatively long leg '72.

At this time, attention is called to the use of an L- shaped member 78providing a vertical flange 80 and a horizontal flange 84, thehorizontal flange 84 having a transverse slot 36 formed therein. Thevertical flange 80 of the member 78 is affixed, as by soldering orbrazing, to a sleeve or tubular bearing $2 which encircles therelatively long leg '72 of the Lshaped rod 68.

The lock assemblage further includes a release lever 96 having astraight shank portion Ell with a cap 94 at the upper end thereof so asto provide a convenient operating handle for the lock assemblage. Therelease lever 9 9t? has a U-shaped portion 96 that provides an upperhorizontal or transverse leg 98, a curved bight segment 1100, and alower horizontal or transverse leg 162. The horizontal leg MP2 isjournalled in a tubular bearing 88 that is secured, as by brazing orsoldering, to the vertical portion 48 and has a stop in the form of asplit washer TAM for preventing the free end of the leg Hi2 from beinginadvertently withdrawn from the bearing 88, the washer being identicalto the one labelled '76 that has already been referred to. The groovefor anchoring the washer 104 has been assigned the reference numeral 1%and the presence of the groove can best be understood from FIGURE 4.

Fixedly carried by the release lever 96, more specifically the lowerhorizontal leg 162 thereof, is a keeper 198 in the form of an ear ortongue that is attached to the lever 90 by brazing or soldering. Inother words, the keeper llltl is integral with the lever 90 and will berocked when the lever is actuated, the previously-mentioned tubularbearing 88 serving as a pivot for such rocking action. The keeper 1% is,however, located at the opposite end of the bearing 83 from the washerEM and therefore assists in preventing unwanted lateral shifting of thelever 90. The keeper ltlS extends downwardly through the transverse slotSt; in the horizontal flange of the mem ber 78 and the lever 9-9 is thusadditionally constrained from lateral movement. By virtue of anoversized aperture 110 formed in the keeper N8, the keeper is permittedto loosely encircle a portion of the Lshaped rod 68, more specificallythe long leg 72 thereof. Whereas the leg 72 is chromium plated, the wallof the aperture lltl is not, thereby presenting only a mild steelsurface that will not damage the rod 68 when gripping the leg 72. A coilspring 112 interposed between the vertical flange (ill of the member '78and the keeper 1% is instrumental in normallyurging the keeper 1th intoa cocked or tilted relationship with respect to the rod 63.

Having presented the foregoing information, the mannet in which my lockassemblage is used for the purpose of maintaining the leg rest 36 at anydesired angular position should be readily understood, From FIGURE 3, itcan be appreciated that the cocked position of the keeper M8 isresponsible for gripping the long leg 72 of the L- shaped rod 63 so thatthe rod is prevented from moving to the right or toward the verticalportion 48 of the inverted L-shaped member 33. The binding or grippingaction due to the tilted position of the keeper 1% produces a force thatis immediately transmitted via the tubular bearing 88 to the verticalportion 48 of the inverted L- shaped member 33. Thus, the obtuse arm 5'4is retained at any selected angular position due to the clamping actionprovided by the keeper 1%. Stated somewhat differently, even if the legrest 36 is at a high position, such as that shown in phantom outline inFIGURE 2, there can be no downward movement and the weight of a personsleg will be supported on the member 53 and the leg will be kept at theelevation shown.

On the other hand, if the user desires to lower the leg rest 36, he canconveniently and quickly do so by pull ing the release lever 90 towardhim, that is, moving the lever 94) in a clockwise direction as shown inFIGURES l3. When the lever 90 is so manipulated, then the keeper 1% ismoved into a more nearly perpendicular relationship with the long leg 72of the rod 68. Due to the clearance provided by the aperture 114), itcan be seen that the more nearly perpendicular relationship permits theleg '72 to slide relative tothe keeper res. Once the user relaxes hispull on the lever W, though, the coil spring 112 immediately biases thekeeper 1% back into the position in which it appears in FIGURE 3. Inother words, the gripping action due to the cocking or tilting of thekeeper 108 is immediately re-established when the user releases hisgrasp on the lever 98. it will be under stood that the user has a veryaccurate control of the lock assemblage and can pivot or rock the leveras in 4 small angular increments that permit the leg rest 36 to belowered to just the right height that is desired.

The hard surface of the rod 68 does not become marred or notched by thekeeper and hence remains smooth and easily controlled. Additionally,where a zinc overcoating is used, a positive friction grip may be maintained, even under high forces. However, since the zinc overcoating isvery thin, the hard undersurface still prevents marring of the rod.Because the flange 86 on the member 78 overlies the relatively long leg'72 of the rod lint and dirt do not tend to collect on the rod andspring but will merely lie on the top surface of the flange from whichit can easily be wiped oil.

It will, of course, be understood that various changes may be made inthe form, details, arrangements and proportions of the parts withoutdeparting from the scope of my invention as set forth in the appendedclaims.

What is claimed:

1. in combination with an adjustable leg rest for wheel chairs includinga generally vertical first member, a second member pivotally connectet.at its upper end to said first member, and means carried on said secondmember for supporting a persons leg, a lock assemblage for said leg restcomprising:

(a) a generally horizontal rod pivotally connected at one end to saidsecond member at a point beneath the pivotal connection of said firstand second member;

(b) a lever having a horizontal U-s'naped portion connected to the firstmember of said leg rest;

(0) a keeper atlixed to the lower leg of said lever having an aperturetherein through which said rod freely extends;

(d) a sleeve encircling said rod so as to permit slidable movement ofsaid rod with respect thereto;

(e) a vertical flange affixcd to one end of said sleeve;

(f) a horizontal flange athxed to the upper end of said vertical flangeand overlying a portion of said rod and havin a transverse slot thereinthrough which said keeper projects; and

(g) a coil spring interposed between said keeper and said sleeve in anencircling relation with said rod for normally cocking said keeper intoa tilted position with respect to said rod so as to cause gripping thereof to thereby prevent movement of said rod and second member toward saidfirst member,

(h) whereby actuation of said lever into a position to cause said keeperto assume a more nearly perpendicular relationship with said rod willallow said rod and second member to move toward said first member.

2. In combination with an adjustable leg rest for wheel chairs includinga generally vertical first member, a second member pivotally connectedat its upper end to said first member, and means carried on said secondmember for supporting a persons leg, a lock assemblage for said leg restcomprising:

(a) a generally horizontal rod pivotally connected at one end to saidsecond member at a point beneath the pivotal connection of said firstand second member;

(b) a lever having a U-shaped portion providing upper and lowerhorizontal legs and a connecting bight;

(c) bearing means on said first member for pivotally supporting thelower leg of said lever;

(d) an upstanding shank portion connected to the free end of the upperleg of said lever for actuating said lever;

(e) a keeper aflixed to the lower leg of said lever between said bearlngmeans and the bight portion thereof, said keeper having an a; erturetherein through which said rod freely extends;

(f) a sleeve encircling said rod so as to permit slidable movement ofsaid rod with respect thereto;

(g) a horizontal flange carried by said sleeve in an overlyingrelationship with a section of said rod and having a transverse slottherein through which said keeper projects, and

(h) a coil spring interposed between said keeper and said sleeve in anencircling relationship with said rod for normally cocking said keeperinto a tilted position with respect to said rod so as to cause grippingthereof to thereby prevent movement of said rod and second member towardsaid first member,

(i) whereby actuation of said lever via said shank portion into aposition to cause said keeper to assume a more nearly perpendicularrelationship with said rod will allow said rod and second member to movetoward said first member.

3. The combination of claim 2 in which:

(a) said rod has a hard and smooth surface, and

(b) the wall of said keeper aperture has a surface n0 harder than thesurface of said rod.

4. The combination of claim 2 including:

(a) a washer element carried at the free end of said lower leg forpreventing removal of said lower leg from said bearing means, and

(b) said keeper residing adjacent the other end of said bearing means.

5. In combination with an adjustable leg rest for wheel chairs includinga generally vertical first member, a second member pivotally connectedat its upper end to said first member, and means carried on said secondmember for supporting a persons leg, a lock assemblage for said leg restcomprising:

(a) a generally horizontal rod pivotally connected at one end to saidsecond member at a point beneath the pivotal connection of said firstand second member;

(b) a lever pivotally connected to the first member of said leg rest;

(0) a keeper atlixed to said lever having an aperture therein throughwhich said rod freely extends;

(d) a sleeve encircling said rod so as to permit slidable movement ofsaid rod with respect thereto;

(e) a flange aifixed to said sleeve and projecting there-' from in anoverlying parallel relationship with a portion of said rod and having atransverse slot therein through which said keeper projects, and

(f) a coil spring interposed between said keeper and said sleeve in anencircling relation with said rod for normally cocking said keeper intoa tilted position with respect to said rod so as to cause grippingthereof to thereby prevent movement of said rod and second member towardsaid first member,

(g) whereby actuating of said lever into a position to cause said keeperto assume a more nearly perpendicular relationship with said rod willallow said rod and second member to move toward said first member.

References Cited by the Examiner UNITED STATES PATENTS 2,520,309 8/50Everest et a1 297433 2,793,682 5/57 Duke 297--433 2,833,081 5/58 Pottern108-9 2,924,299 2/60 Kanzelberger et al 188-67 3,021,889 2/62 Mize297-429 FRANK B. SHERRY, Primary Examiner.

1. IN COMBINATION WITH AN ADJUSTABLE LEG REST FOR WHEEL CHAIRS INCLUDINGA GENERALLY VERTICAL FIRST MEMBER, A SECOND MEMBER PIVOTALLY CONNECTEDAT ITS UPPER END TO SAID FIRST MEMBER, AND MEANS CARRIED ON SAID SECONDMEMBER FOR SUPPORTING A PERSON''S LEG, A LOCK ASSEMBLAGE FOR SAID LEGREST COMPRISING, (A) A GENERALLY HORIZONTAL ROD PIVOTALLY CONNECTED ATONE END TO SAID SECOND MEMBER AT A POINT BENEATH THE PIVOTAL CONNECTIONOF SAID FIRST AND SECOND MEMBER; (B) A LEVER HAVING A HORIZONTALU-SHAPED PORTION CONNECTED TO THE FIRST MEMBER OF SAID LEG REST; (C) AKEEPER AFFIXED TO THE LOWER LEG OF SAID LEVER HAVING AN APERTURE THEREINTHROUGH WHICH SAID ROD FREELY EXTENDS; (D) A SLEEVE ENCIRCLING SAID RODSO AS TO PERMIT SLIDABLE MOVEMENT OF SAID ROD WITH RESPECT THERETO; (E)A VERTICAL FLANGE AFFIXED TO ONE END OF SAID SLEEVE; (F) A HORIZONTALFLANGE AFFIXED TO THE UPPER END OF SAID VERTICAL FLANGE AND OVERLYING APORTION OF SAID ROD AND HAVING A TRANSVERSE SLOT THEREIN THROUGH WHICHSAID KEEPER PROJECTS; AND (G) A COIL SPRING INTERPOSED BETWEEN SAIDKEEPER AND SAID SLEEVE IN AN ENCIRCLING RELATION WITH SAID ROD FORNORMALLY COCKING SAID KEEPER INTO A TILTED POSITION WITH RESPECT TO SAIDROD SO AS TO CAUSE GRIPPING THEREOF TO THEREBY PREVENT MOVEMENT OF SAIDROD AND SECOND MEMBER TOWARD SAID FIRST MEMBER, (H) WHEREBY ACTUATION OFSAID LEVER INTO A POSITION TO CAUSE SAID KEEPER TO ASSUME A MORE NEARLYPERPENDICULAR RELATIONSHIP WITH SAID ROD WILL ALLOW SAID ROD AND SECONDMEMBER TO MOVE TOWARD SAID FIRST MEMBER.